1. Field of the Invention
The present invention relates to automobile door lock warmers, and more particularly pertains to a new and improved automobile door lock warmer in which a fan blows heated air onto the door lock cylinder. In cold climates, and particularly in cold and humid climates, freeze-up of automobile door locks is an annoying problem. This freeze-up is caused by an accumulation of moisture within the door lock, and also by the simple freezing of lubricants within the lock mechanism. The problem is particularly acute in regions affected with freezing rain. Also, in very cold climates, the hands of an automobile owner may become numb by the cold to an extent where it is impossible to manipulate the key in the lock. This, in conjunction with the aforementioned lock freeze-up problems has frustrated many a vehicle owner.
2. Description of the Prior Art
Various types of automobile door lock warmers are known in the prior art. A typical example of such an automobile door lock warmer is to be found in U.S. Pat. No. 2,530,513, which issued to A. Drugan on Nov. 21, 1950. This patent discloses a device for electrically heating the door key of a motor vehicle by electrical resistance elements. The device is attached to the exterior surface of an automobile. U.S. Pat. No. 3,192,359, which issued to W. Swindall on June 29, 1965, discloses an electrical heater for automobile door lock cylinders. The device is mounted within the door frame of an automobile and may be manually or automatically actuated in response to a freezing temperature. U.S. Pat. No. 3,662,149, which issued to R. Lipinski on May 9, 1972, discloses a thermistor automobile door lock heater. The thermistor has an electrical resistance which rises abruptly at a temperature near thirty two degrees Fahrenheit. Thus, at temperatures below thirty two degrees Fahrenheit the thermistor resistance will decrease causing an activation of the door lock heater. U.S. Pat. No. 4,303,825, which issued to N. Jaronen on Dec. 1, 1981, discloses a portable electric heating device for thawing motor vehicle door locks. An electrically heated probe is insertable into the keyhole of a frozen lock. U.S. Pat. No. 4,442,341, which issued to Y. Lesquereux et al on Apr. 10, 1984, discloses an electric heating device for vehicle lock cylinders which utilizes a thermistor heating element embedded in a heat conductive electrically insulative silicone-based compound. A U-shaped sheet metal strip electrically connected to one contact of the heating element is arranged to contact the lock cylinder.
While the above mentioned devices are suited for their intended usage, none of these devices utilizes an electric fan for circulating warmed air around an automobile door lock cylinder. Also, none of the above devices provides for both heating of the door lock cylinder and of the operator's hands and the door key. Further, none of the aforesaid devices utilizes a helical rib for swirling warmed air around an automobile door lock cylinder. Inasmuch as the art is relatively crowded with respect to these various types of automobile door lock warmers, it can be appreciated that there is a continuing need for and interest in improvements to such automobile door lock warmers, and in this respect, the present invention addresses this need and interest.